Cooling passages in cast aluminum cylinder heads and blocks



April 28, 1964 F. v. CURTIS 3,130,461

COOLING PASSAGES IN CAST ALUMINUM CYLINDER HEADS AND BLOCKS Filed Aug.1, 1961 5 Sheets-Sheet 1 INVENT OR PEER/S V CURTIS April 28, 1964 F. v.CURTIS 3,130,461

COOLING PASSAGES IN CAST ALUMINUM CYLINDER HEADS AND BLOCKS Filed Aug.1, 1961 3 Sheets-Sheet 2 Li I J I (I 37 I \ao -23 3o 3| 3| EI E: 48

INVENTOR PEER/5 V. CURTIS BY Q 4 1...

g ATTORNEY April 28, 1964 F. v. CURTIS 3,130,451

COOLING PASSAGES IN CAST ALUMINUM CYLINDER HEADS AND BLOCKS I Filed Aug.1, 1961 3 Sheets-Sheet'3 I so\ INVENIOR ,FERR IS V. CUR 77$ UnitedStates Fatent ()fi ice 3,130,461 Patented Apr. 28, 1964 3,139,461 COGL GFASSAGES TN QAST ALUPt HNTM CYLTNDER HADS AND BLGEKS Ferris V. Curtis,Flint, Mich, assignor to General Motors Corporation, Detroit, Mich, acorporation of Delaware Filed 1, 1961, Ser. No. 128,517 3 Claims. (Cl.22-263) This invention relates to an internal combustion engine cylinderhead or engine block construction in which there are located coolingfluid passages through which inlet and exhaust passages extend. Moreparticularly, this invention relates to a cylinder head or engine blockconstruction and the process of making these or like objects wherebypreformed inserts are used in a mold cavity to provide cooling fluidpassages and passages for inlet and exhaust gases.

With the increasing complexity of cylinder heads and engine blocks alongwith the desire to form a very definite relationship between the partsthat cooperate with the cylinder head or engine block, it has becomemore important to provide intricate passages within such members forcooling these cooperating parts without materially increasing theexpense of manufacture. It has previously been known to cast moltenmetal about a conduit of copper to form a cylinder head having necessarycooling passages. This type of construction does not solve present daycylinder head or engine block requirements wherein there is required agreater intricacy of cooling passages and an association between thecooling passage surface and the poured casting to result in maximum heatconductivity to the cooling fluid.

One of the objects of this invention is to provide an internalcombustion engine cylinder head or engine block with cooling passages,wherein the cooling passages are formed or stamped parts, thereby givinggreater flexibility in design and intricacy in construction withoutadded expense. It is another object of this invention to use a preformin a mold cavity to provide the cooling passages, the preform beingintegrally associated with the subse' quently poured cylinder head orengine block, thereby resulting in maximum heat conductivity between thecast member and the cooling fluid passages. It is a further object ofthis invention to provide a process by which a cylinder head or the likewith passages therein, may be reliably and easily formed. A stillfurther object of this invention is to produce a cylinder head by usinga stamped preformed conduit placed within the cylinder head mold cavityto provide fluid cooling passages in the cast article. The preform maybe made by sheet metal stampings securely fastened together to providedesired intricate and complex cooling fluid passages in the castcylinder head or engine block. Other objects of this invention willbecome apparent upon analysis of the following description, referencebeing made to the accompanying drawings wherein a preferred form of theinvention is clearly shown.

In the drawings:

FIGURE 1 is a plan view of the cooling fluid preform.

FIGURE 2 is a cross-sectional view taken along line 2-2 of FIGURE 1.

FIGURE 3 is a fragment of a cross-sectional view taken along line 33 ofFIGURE 1.

FIGURE 4 is a cross-sectional side view of an intake liner.

FIGURE 5 is a cross-sectional view of an exhaust liner.

FIGURE 6 is a cross-sectional side view of the cylinder head mold havingthe cooling fluid passage preform and the inlet and exhaust linersassembled therein.

FIGURE 7 is a cross-sectional side view of a cylinder head with thecooling fluid passage preform and inlet and exhaust gas liners moldedtherein.

FIGURE 8 is a fragmentary view showing the cylinder head cast about thecooling passage preform as illustrated in FIGURE 3.

The cooling passage preform as shown in FIGURES 1 through 3 includes twosheet metal members 1 and 2 secured together by crimping or the like,and inlet and exhaust conduits 3 and 4 secured to the sheet metalportion it by means of an enlarged portion 5 and a flange 6 on the inletand exhaust conduits 3 and 4 cooperating with an upset portion 7 in thesheet metal portion 1. A cylindrical conduit 3 has two upstandingportions 9 and it) that are sealingly secured to the sheet metal portion2 by a press fit or the like with a flanged aperture 11 in the sheetmeal portion 2. Conduit 8 further has a spiral 12 extending between theupstanding portions 9 and It) to direct cooling fluid around an exhaustvalve stem, as will be hereinafter described. The spiral 12 may consistof one or more turns depending upon the necessity of cooling of theexhaust valve stem, such being dependent upon the actual operatingconditions of a particular engine. Sheet metal portions 1 and 2 haveapetrures 13 and 14 extending therethrough, such apertures beingnecessary to accommodate intake and exhaust valves. Similar apertures 15and 16 can be incorporated in the preform for a plurality of spark plugsor other accessories, if desired. These apertures are formed by havingupstanding flanges on the lower sheet metal portion 1 engaging the uppersheet metal portion 2. More particularly, as shown in FIGURE 2, theupstanding flanges 17 and 18 of the sheet metal portion 1 form theintake and exhaust passages respectively and upstanding portions 19 and29 on the upper sheet metal portion 2 provide a press of fused fit withthe portions 17 and 18 to form a secure enclosed assembly. Additionally,the upper sheet metal portion 2 is crimped around its outer edge aboutthe lower sheet metal portion 1 in a well known manner. Similarly, theupper sheet metal portion 2 can be crimped at 21 and 22 about the lowersheet metal portion 1.

Inlet and exhaust conduits 3 and 4 provide means for introducing andremoving cooling fluid to and from the cooling passages formed by thepreform. The actual location of the inlet and exhaust conduits 3 and 4will depend upon a specific assembly and in particular, the type ofengine in which the preforms are to be used. Since engine cylinder headstake any one of a number of shapes, it should be appreciated thatlikewise, the applicants preform may take any one of a number of shapesto adapt to the particular cylinder head arrangement. Although theembodiment disclosed and described in this specification discloses apreform adapted only to a single cylinder, use of this invention couldobviously involve and include provision of a preform for a multiplecylinder engine. Likewise, the preform could be used in the type ofengine wherein each cylinder is separately cooled. Dirnples ordepressions 23 may be provided in the lower sheet metal portion 1 toincrease the flow characteristics of the cooling fluid and the surfacearea of sheet 1 so that a greater amount of fluid is warmed therebyobtaining a more rapid cooling characteristic. These dimples 23 could beformed in the upper sheet 2 alone or in the lower portion 1 as well asto increase the rigidity of the preform and aid in securing the preformto the poured molten cylinder head casting.

FIGURES 4 and 5 show intake and exhaust liners, respectively. Theseliners consist primarily of a stamped sheet metal tube, the specificdesign of which will be dependent upon the actual cylinder headconstruction. The intake liner 24- has an aperture 25 extending througha portion 26 that is offset from the regular curvature of tube 24. Theaperture 25 is provided for the conventional intake valve stem. Theexhaust liner 27 similarly has an aperture 28 in offset portion 29 forthe exhaust valve stem.

The assembly of the fluid passage preform and the intake and exhaustliners in the mold cavity is shown in FIGURE 6. Fingers 3t) arespot-welded or otherwise secured to the preform to support the preformwithin the mold cavity upon shoulder 31 of lower mold piece 32. Apermanent core 33 of steel or the like is inserted in the lower moldcavity. This permanent core 33 has two upstanding portions 34 and 35which extend upwardly beyond the lower mold cavity 32. Tapered portions36 and 37 on these upstanding portions are slightly tapered and providethe surfaces upon which the intake and exhaust liners are assembledprior to the molding operation. The upstanding portions 34 and 35further have shoulders 38 and 39, respectively, that engage the linersadjacent apertures 25 and 28, while upstanding portions 34 and 35 extendthrough these apertures and seal off the flow of molten cylinder headmetal to the intake and exhaust passages. A helical conduit 8 extendsaround the upstanding portion 35 so that cooling fluid can be circulatedaround the exhaust valve stems during operation of engines utilizingcylinder heads and engine blocks incorporating the previously describedcasting preforms. The exhaust valve gets considerably hotter than theintake valve and the heat problems with this valve are somewhat moredifricult and require the necessity of additional cooling means aroundthe efiaust valve stem, such as provided with the helix coil 8.

An upper mold portion 4% has a cavity which determines the externaldimensions of the cylinder head therein. This upper mold 40 hasextensions 41 and 42 that engage respective outer edges of the intakeand exhaust liners. Extensions 41 and 42 prevent flow of molten metalinto the intake and exhaust passages. Apertures 43 and 44 are providedin this upper mold to vent hot exhaust gases from the intake and exhaustpassages to atmosphere. The upper mold 4% may necessarily have to becomposed of a plurality of pieces due to the relationship of the uppermold with the intake and exhaust liners. For example, this upper moldcould be divided into two pivotally associated halves, the halvesmounted to be pivoted into association with the intake and exhaustliners subsequent to their being placed within the mold cavities.

After the upper mold 40 is positioned upon the lower mold 32 and thepreform and the intake and exhaust liners are assembled in the moldcavity, mold cap 45 is assembled upon the upper mold 4i? so that cap 45engages the upstanding portions 34 and 35 to complete the molding cavityfor an internal combustion engine casting.

Referring now to FIGURES 7 and 8, molten metal is then poured intopassage 46 or 47 to form the cylinder head H and to associate thepreform and the intake and exhaust passages with the cylinder head. Thepoured cylinder head may be associated integrally with the cylinder,such being formed between the lower mold 32 and the permanent core 33 inspace 48 shown in FIGURE 6. Special passages, not shown, are provided inthe lower mold 32 through which the inlet and exhaust conduits 3 and 4extend.

An important feature of the applicants invention is the use of aluminumas a material for both the intake and exhaust liners and for the fluidpassage preform members l and 2 as well as for conduits 3, 4 and 8. Useof aluminum members in association with a conventional aluminum castcylinder head, allows the preform and liners to become integrallyassociated with the aluminum engine castings during the casting processresulting in a continuous integral aluminum composite body. The preformand liners are properly cleaned and treated by a flux in a well knownmanner prior to the casting operation so that there will be a rigidintegral association between the preform, liners and the casting.

The use of aluminum liners and preforms with an aluminum castingprovides a cylinder head construction functionally equivalent to thosecastings which do not use preforms or liners. Among the importantadvantages of this use of preforrns and liners are that a more reliablecasting is produced and a process which avoids the com plexity of sandcores, such as the cleaning thereof, is provided. Additionally, anintegral aluminum cylinder head and preform construction avoids anyrelative expansion problems or bonding difiiculties that may exist whereunlike materials are used. However, should any difficulty in bonding theairtight preformed inserts to the molten aluminum or casting metalarise, the inserts can be specially coated to facilitate the desiredadherence. It is recognized that casting aluminum about an aluminumpreform or liner presents certain problems in that the heat conductivityof aluminum could possibly result in the molten aluminum metalexcessively melting the aluminum preforms and liners. This can easily beavoided by proper selection of the preform and liner alloy material.

While the embodiment above described is the preferred form it should beunderstood that this invention could take many forms depending upon thetype of construction in which preform and liner passages are foundnecessary. Therefore, it is to be understood that the invention is notto be restricted to the above disclosure but that the invention shouldhave the scope as determined by the following claims.

What is claimed is:

1. A method of casting an aluminum internal combustion engine cylinderhead comprising the steps of positioning a permanent core within a lowermold cavity, positioning and fastening upstanding support members on thetop surface of said permanent core, welding supporting tabs to a hollowpreformed aluminum alloy insert, placing said hollow insert over saidupstanding support members so that said support tabs rest upon ashoulder in said lower mold cavity, placing aluminum alloy tubularintake and exhaust gas liners upon said upstanding support members,attaching fluid inlet and outlet ducts to said hollow preformed insert,positioning an upper mold portion upon said lower mold, inserting a moldcap member within said upper mold portion, and pouring a molten aluminumalloy within said assembled mold cavity causing an integral bond withsaid preformed insert and said gas liners upon solidification of saidmolten alloy.

2. A method of casting an aluminum internal combustion engine componentcomprising the steps of positioning a permanent core within a moldcavity, inserting a hollow aluminum alloy preformed insert within saidmold cavity, placing aluminum alloy tubular gas passage liners upon saidpermanent core, connecting fluid inlet and outlet means to saidpreformed insert, positioning an upper mold portion upon said moldcavity to form a complete mold cavity, and pouring a molten aluminumalloy within said mold cavity whereby an engine component comprising anintegrally bonded hollow preformed insert 7 and gas passage liners isformed.

3. A method of forming an aluminum internal combustion engine componentcomprising the steps of placing a hollow preformed aluminum alloy insertwithin a lower mold cavity, positioning a first end of an aluminum alloygas duct liner Within said preformed insert, placing an upper moldportion upon said lower mold, attaching a second end of said gas ductliner upon an extension of said upper mold portion, inserting a mold capmember Within said upper mold portion to form a mold cavity, and pouringa molten aluminum alloy within said cavity causing integral bonding ofsaid gas duct liner and said preformed insert with said engine componentupon solidification of said molten alloy.

References Cited in the file of this patent UNITED STATES PATENTS DietzFeb. 20, 1940 Towler Dec. 24, 1940 Irgens Oct. 12, 1943 Stevenson Mar.1, 1949 George Apr. 18, 1950 Watson June 28, 1955 Douglas Sept. 25, 1956Atchison Feb. 19, 1957 Burrows et a1. Nov. 4, 1958 Rarey et al. June 21,1960

2. A METHOD OF CASTING AN ALUMINUM INTERNAL COMBUSTION ENGINE COMPONENTCOMPRISING THE STEPS OF POSITIONING A PERMANENT CORE WITHIN A MOLDCAVITY, INSERTING A HOLLOW ALUMINUM ALLOY PREFORMED INSERT WITHIN SAIDMOLD CAVITY, PLACING ALUMINUM ALLOY TUBULAR GAS PASSAGE LINERS UPON SAIDPERMANENT CORE, CONNECTING FLUID INLET AND OUTLET MEANS TO SAIDPREFORMED INSERT, POSITIONING AN UPPER MOLD PORTION UPON SAID MOLDCAVITY TO FORM A COMPLETE MOLD CAVITY, AND POURING A MOLTEN ALUMINUMALLOY WITHIN SAID MOLD CAVITY WHEREBY AN ENGINE COMPONENT COMPRISIG ANINTEGRALLY BONDED HOLLOW PREFORMED INSERT AND GAS PASSAGE LINERS ISFORMED.